The long term objective of this research work is to gain a better understanding of the mechanism of protein synthesis initiation in red blood cells. In this research we propose to study the roles of different factors such as peptide chain initiation factors and protein synthesis inhibitors that are involved in the regulation of protein synthesis in red blood cells. We will analyze how these factors change under different physiological conditions and control cellular processes such as aging, anemia and red cell-differentiation. Also included in this research is a comparative study of the mechanism of protein synthesis initiation in red blood cells with similar processes in other cell types such as Escherichia coli. This study will include a comparison of the basic steps of protein synthesis initiation in these cell types, the recognition characteristics of the peptide chain initiation factors, initiator tRNAs and protein synthesis inhibitors. Such studies will reveal if a specific process or a specific factor is unique for red blood cell protein synthesis.